Acrylic coating composition for refinishing flexible substrates

ABSTRACT

THE COATING COMPOSITION IS USEFUL FOR REPAIRING THE FINISH OF FLXIBLE AUTOMOBILE AND TRUCK BUMPERS AND COMPRISES A BLEND OF THE FOLLOWING POLYMERS: (1) A COPOLYMER OF METHYL METHACRYLATE AND AN ALKYL ACRYLATE OR AN AKYL MTHACRYLATE HAVING 2-12 CARBON ATOMS IN THE ALKYL GROUPS; (2) A COPOLYMER OF METHYL METHACRYLATE AND AN ADHESION OF PROMOTING MONOMER SUCH AS THE 3-2-METHACRYLOXYETHYL (2,2 SPIRO CYCLOHEXYL OXAZOLIDINE); (3) A PLASTICIZER WHICH IS EITHER A PHTHALATE ESTER SUCH AS BUTYL BENZYL PHTHALATE OR BUTYL CYCLOHEXYL PHTHALATE OR AN ALKYD RESIN; THE NOVEL COMPOSITION CAN BE BLENDED WITH OTHER PIGMENTED ACRYLIC POLYMER COATING COMPOSITIONS TO FORM A HIGH QUALITY REFINISH COMPOSITION FOR FLEXIBLE BUMPERS.

-United States Patent 3 829 397 ACRYLIC COATING coMPosrrroN FORREFINISHING FLEXIBLE SUBSTRATES Ronald J. Sheppard, Flushing, Mich,assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del.

No Drawing. Filed Aug. 30, 1972, Ser. No. 285,094

' Int. Cl. C08f 15/18, 37/06, 45/40 US. Cl. 260-31.8 M 3 Claims ABSTRACTOF THE DISCLOSURE The coating composition is useful for repairing thefinish of flexible automobile and truck bumpers and comprises a blend ofthe following polymers:

( 1) a copolymer of methyl methacrylate and an alkyl acrylate or analkyl methacrylate having 2-12 carbon atoms in the alkyl groups;

(2) a copolymer of methyl methacrylate and an adhesion of promotingmonomer such as the 3-2-methacryloxyethyl (-2,2 spiro cyclohexyloxazolidine);

(3) a plasticizer which is either a phthalate ester such as Y Y butylbenzyl phthalate or butyl cyclohexyl phthalate or an alkyd resin;

the novel composition can be blended with other pigmented acrylicpolymer coating compositions to form a high quality refinish compositionfor flexible bumpers.

BACKGROUND OF THE INVENTION This invention is related to a polymericcoating composition and in particular, to a polymeric coatingcomposition that is useful for refinishing flexible substrates.

The automobile and truck manufacturing industry is utilizing bumperscoated with a flexible material such as a high density polyurethanefoam, a hydrocarbon rubber or polyvinyl chloride. These flexible bumpersare coated in the factory with a primer and a topcoat that requiresbaking to cure the resulting finish. But when these automobile or truckbumpers become damaged in use, an air dry refinish composition ispreferred for low cost maintenance. The novel coating composition ofthis invention has air drying characteristics and adheres to the primedflexible substrate of the bumper and also to the factory applied topcoatof the bumper. Also, the novel coating composition can be blended withother pigmented acrylic compositions to form a high quality finish forflexible bumpers.

SUMMARY OF THE INVENTION A coating composition comprising 10-50% byweight of film forming binder and corresponding 90-50% by weight of anorganic solvent for the binder wherein the binder consists essentiallyof 1) 35-65% by Weight, based on the Weight of the binder, of acopolymer consisting essentially of 80-90% by Weight of methylmethacrylate and correspondingly 10- 20% by Weight of an alkyl acrylateor an alkyl methacrylate having 2-12 carbon atoms in the alkyl groups;

(2) 5-20% by Weight of the copolymer consisting essentially of 85-95% byWeight of methyl methacrylate and 3,829,397 Patented Aug. 13, 1974 5-15by Weight of an adhesion promoting monomer of the formula DESCRIPTION OFTHE INVENTION The novel coating composition of this invention containsabout 10-50% by weight of the film forming binder and correspondinglyabout 90-50% by weight of an organic solvent for the binder. The novelcoating composition can contain a 01-20% by weight pigment butpreferably is utilized as a clear coating composition.

The film forming binder utilized in the novel coating composition ofthis invention contains a blend of acrylic polymers and a plasticizer.The acrylic polymers have a relative viscosity of about 1.03-1.50,preferably about 1.10-1.25. The relative viscosity is a value obtainedby dividing the efliux time of the solution of the polymer by the efliuxtime of a solvent used to form the solution. The efliux times aremeasured according to the procedure of ASTMD-445-46 T method B, using asthe polymer solution 0.25 gram of the polymer and 50 cubic centimetersof ethylene dichloride as a solvent. The efiflux times are measured at25 C. using standard apparatus sold under the designation of a modifiedOstwald viscometer.

These acrylic copolymers are prepared by conventional polymerizationtechniques in which the monomers, the solvents, and polymerizationcatalysts are charged into a reaction vessel and the reaction mixture isheated to about 50-200 C. and reacted from about 1 to 6 hours to form apolymer having the afore-mentioned viscosity range.

The following are typical of polymerization catalysts which can be usedto prepare these polymers such as azo, bis-isobutyronitrile, azo-bis-(a,gamma dirnethylvaleronitrile), benzoyl peroxide, t-butylperoxypivalate,di-tertiary-butyl peroxide and the like.

Typical solvents which are used to prepare the acrylic polymers utilizedin this invention are toluene, xylene, butylacetate, acetone,methylisobutylketone, methylethyl ketone, butyl alcohol, and otheraliphatic, cycloaliphatic, aromatic hydrocarbons, esters, ethers,ketones and alcohols. I

The novel coating composition of this invention contains 35-65% byweight, based on the weight of the binder of a coplymer of -90% byweight of methyl methacrylate and correspondingly 10-20% by Weight of analkyl acrylate or an alkyl methacrylate and has 2-12 carbon atoms in thealkyl groups. Preferably, novel coating composition contains 46-56% byweight, based on the weight of the binder of this copolymer.

Typical alkyl acrylates or alkyl methacrylates that can be utilized inpreparing this copolymer are ethyl acrylate, propyl, acrylate, butylacrylate, isobutyl acrylate, hexyl acrylate, 2 ethyl hexyl acrylate,nonyl acrylate, pentyl acrylate, lauryl acrylate, ethyl methacrylate,propyl methacrylate, butyl methacrylate, isobutyl methacrylate, hexylmethacrylate, 2 ethyl hexyl methacrylate, octylmethacrylate, nonylmethacrylate, pentyl methacrylate and lauryl methacrylate.

One preferred copolymer contains 82% by weight of methyl methacrylateand 18 by weight of butyl acrylate.

A novel coating composition contains 5-20% by weight and preferably -14%by weight of an adhesion promoting copolymer of 85-95% by weight ofmethyl methacrylate and 5-15% by weight of the adhesion promotingmonomer.

The adhesion promoting monomer utilized in the above wherein n is 1-2and m is 2-3, R ant R are hydrogen, phenly, benzyl or an alkyl grouphaving 1-12 carbon atoms. Typical compounds of this type are3-(2-methacryloxyethyl) 2,2 spirocyclohexyl oxazolidine, 3-(2-ethylacryloxymethyl)-2,2-spirocyclohexy1 oxazolidine and the like. Thepreferred compound is 3- (Z-methylacryloxyethyl)-2,2-spiro cyclohexyloxazolidine.

The novel coating composition contains -50% by weight, and preferably38-42% by weight of a plasticizer which is either phthalate esterplasticizer or an alkyd resin plasticizer. Typical phthalate esterplasticizers that can be used are aromatic phthalate esters orcycloaliphatic phthalate esters such as butyl benzyl phthalate or butylcyclohexyl phthalate.

Typical alkyd resins which can be used are the reaction product ofnondrying oil fatty acids, a polyhydric alcohol, dicarboxylic acid orits anhydride. Typical nondrying oil fatty acids which can be used arecottonseed oil fatty acids, castor oil fatty acids, coconut oil fattyacids, and the like. Typical polyhydric alcohols that can be used areglycerin, pentaerythritol, trimethylolethane, trimethylolpropane,glycols such as ethylene glycol, propylene glycol, bu-tanediol,pentanediol and the like. Typical dicarboxylic acids or the anhydridesthereof can be used to prepare this alkyd resin plasticizer are phthalicacid, phthalic anhydride, isophthalic acid, terephthalic acid, adipicacid, sebacic acid, succinic acid, maleic acid, maleic anhydride,fumaric acid and the like.

It may be desirable to incorporate a small portion of mono-carboxylicaromatic acid into the alkyd resin plasticizer. Typical acids that canbe used are benzoic acid, paratertiarybutylbenzoic acid, phenolaceticacid, triethyl benzoic acid and the like.

The alkyd resin plasticizers are utilized in the novel composition ofthis invention, preferably having an acid number of about 2-25,preferably about 5-14 and are about 5-7 acid number units from the gelpoint of the alkyd resin.

One preferred alkyd resin used in this invention is the esterificationproduct of coconut oil, ethylene glycol and phthalic acid or phthalicanhydride and the resulting product contains coconut oil/61% ethyleneglycol phthalate/4% ethylene glycol.

Polyester plasticizers can also be used. Any of the aforementionedpolyhydric alcohols and dicarboxylic acids can be used to form thesepolyesters. Also, small amounts of the above monocarboxylic acids can beincorporated into these polyesters. Typically useful polyesterplasticizers are as follows: adipic acid/phthalic anhydride/ethyleneglycol/benzoic acid in a molar ratio of 1.5/ 1.5/4.0/ 1.9; adipicacid/phthalic anhydride/ethylene glycol/neopentyl glycol/benzoic acidmodified with propyl imine in a weight ratio of 36/27.5/l5.3/17.4/3.8//3.8.

The novel coating composition of this invention preferably is utilizedas a clear but can be pigmented with any of the conventional pigments.Typical pigments which can be used are metallic oxides such as titaniumdioxide, iron oxide, zinc oxide and the like, metal hydroxides, metalflakes such as aluminum flake, metal powders, chromates, sulfates,carbonates, carbon black, silica, talc, phthalocyanine blues and greens,and other organic pigments and dyes.

The novel coating composition is applied by conventional techniques suchas spraying, electrostatic spraying, dipping, brushing, flow coating andthe like to a flexible substrate. The novel composition can be appliedto a variety of flexible substrates such as filler panels, moldings,extension panels and the like. But the primary use for the novel coatingcomposition of this invention is to refinish flexible bumpers which arecoated with one of the following: a high density polyurethane foam, ahydrocarbon rubber such as an ethylene-propylene terpolymer sulfurcurable elastomer, styrene-butadiene rubber, polyvinyl chloride and thelike.

Preferably the technique that is used to refinish bumpers is to apply aclear coating of the novel coating composition of this invention about0.1-1.0 mils in thickness and then allows this coating to air-dry andthen apply a second pigmented coating about 1-4 mils in thickness andthen allow this coating to air-dry. This second pigmented coating is ablend of the clear coating composition of this invention and a pigmentedcoating composition.'

Pigmented coating compositions of a variety of acrylic enamels,lacquers, repair enamels, and repair lacquers can be blended with thenovel coating composition of this invention and the color of the bumpercan be matched without the development of a mill base for thenovelcoating composition of this invention. The compatibility of thenovel coating of this invention makes this technique possible.

The novel coating composition of this invention either alone or oneblended with one of the aforementioned pigmented compositions provides afinish upon drying which is durable, flexible and glossy and makes anattractive finish for flexible automotive and truck bumpers. Theadhesion of the novel composition is particularly good to the primedflexible bumper substrate and the novel composition also has goodadherence to either the lacquer or the enamel coating which wasoriginally used to coat the flexible bumper. These characteristics alongwith the air-drying properties of the novel coating composition of thisinvention makes the composition particularly attractive for the refinishof flexible automotive and truck bumpers and other flexible automobileand truck parts.

When the novel coating composition of this invention is utilized withanother pigmented coating composition, generally 40-60% by volume of thenovel coating composition of this invention is blended withcorresponding 60-40% by volume of another pigmented coating composition.These pigmented coated compositions generally contain 0.1-20% by weightof pigment and l0-50% by weight of the film-forming binder. Any of theaforementioned pigments can be used therein.

One pigmented coating composition which provides a high quality refinishfor acrylic enamels contains (A) 40 to by weight, based on the weight ofthe binder of a polymer of (1) 70 to by weight, based on the weight ofthe polymer, of methyl methacrylate;

(2) less than about 20% by weight, based on the weight of the polymer,of an alkyl acrylate or alkyl methacrylate 2-12 carbon atoms in thealkyl groups (typical ester have been mentioned above);

(3) 3-25% by weight based on the weight of the polymer, a monovalentaminoester radical attached to the backbone of the carbon atoms of thepolymer backbone that has the formula ti; 1km

wherein R is a saturated hydrocarbon group of 3-21 carbon atoms or anunsaturated hydrocarbon group of 3-21 carbon atoms; R is hydrogen, andalkyl group having 1-4 carbon atoms or R is H, an alkyl group having 1-4carbon atoms, R is a saturated hydrocarbon group having 2-20 carbonatoms or an unsaturated hydrocarbon group having 2-20 carbon atoms.

One particularly preferred composition of this type which can be blendedwith the novel coating composition of this invention has a film formingbinder which consists essentially of (A) 50-60% by weight, based on theweight of the binder of a polymer that contains (1) 78-82% by weight ofmethyl methacrylate,

(2) 12-14% by weight of ethyl acrylate,

(3) -8% by weight of a monovalent amino ester groups attached to thecarbon atoms of the backbone of the polymer of the formula where R ishydrogen or methyl and (B) 50-40% by weight, based on the weight of thebinder of an acrylic oxazoline polymer of (1) 53-57% by weight of methylmethacrylate, (2) 13-17% by weight of ethyl acrylate, (3) 3-7% 'byweight of acrylonitrile,

6 (4) 23-27% by weight of a compound of the formula ll om-o-o-n' H C-C oI\II\CH o-( i-Iv where R is a hydrocarbon group of tall oil fatty acidsand R is a hydrocarbon group of tall oil fatty acids less a CH group.

The aforementioned pigmented coating composition is prepared accordingto the teachings of Walus et a1. U.S. Pat. 3,488,307 issued Jan. 6,1970.

Another refinish composition which is particularly useful for repairingacrylic lacquer coatings contains 40- 60% by volume of the novel bindercomposition of this inventio nand correspondingly 60-40% by volume of apigmented coating composition that contains 01-20% by weight of pigmentand 10-50% by weight of a film forming binder of 70-90% by weight, basedon the weight by binder, of

polymethyl methacrylate or a copolymer of methyl methacrylate or amixture of polymethyl methacrylate and a copolymer of methylmethacrylate and a copolymer of methyl methacrylate;

10-30% by weight, based on the weight of the binder, of

cellulose acetate butyrate that has a 0.1-20 seconds viscosity,preferably 0.5-4 seconds viscosity which is measured at 25 C. accordingto ASTM D-1343-56 and has a butyryl content of about 30-55% by weight.

One preferred pigmented coating composition of this type contains 20-30%by weight, based on the Weight of the binder, of

polymethyl methacrylate;

5-15% by weight, based on the weight of the binder, of the copolymer ofmethyl methacrylate and diethyl aminoethyl methacrylate;

30-40% by weight, based on the weight of the binder, of a copolymer ofmethyl methacrylate and butyl acrylate and 15-30% by weight of celluloseacetate butyrate having a 1 to 3 second viscosity and a butryl contentas indicated above.

Another coating composition which is particularly useful for repairingacrylic lacquers comprised 40-60% by volume of the coating compositionof this invention and correspondingly 60-40% by volume of a pigmentedcomposition that contains 0.1 to 20% by weight pigment and 10-50% byweight of a film forming binder. The film forming binder comprises (A)40-60% by weight, based on the weight of the binder of an acrylicoxazoline polymer described above (B) 60-40% by weight, based on weightof the binder of cellulose acetate butyrate that has a viscosity of 0.5-20 seconds measured as indicated above and a butyryl content of 30-55%by weight; and

(C) 0-10% by weight of an organic plasticizer.

One preferred pigmented composition of this type contains (A) 40-50% byweight of a polymer of 53-57% by weight of methyl methacrylate,

13-17% by weight of ethyl acrylate,

. t 7 37% by weight of acrylonitrile, and 23-27% by weight of a compoundof the formula om-o-ii-n -r o N CHz-O-C-R' i C=CH1 1km wherein R is ahydrocarbon group of tall oil fatty acids and R is a hydrocarbon groupof tall oil fatty acids less a CH group. (B) 47-57% by weight ofcellulose acetate butyrate has a l-3 second viscosity and butyrylcontent of 3540%,

by weight (C) 36% by weightof butyl cyclohexyl phthalate.

The acrylic oxazoline polymers mentioned above can be prepared accordingto Donatello et al. US. 3,553,124 issued Jan. 5, 1971.

The above blends can be applied according to the aforementionedconventional techniques to the aforementioned flexible substrates inparticular primed flexible bumpers of high density polyurethane foamreinforced with steel and hydrocarbon rubber bumpers reinforced withsteel and air dried to form high quality finishes.

The following examples illustrate the invention. All quantities areshown on a weight basis unless otherwise specified.

EXAMPLE 1 The coating composition is prepared by blending together thefollowing ingredients:

Parts byweight The above ingredients are thoroughly blended together toform a clear coating composition which has a binder solids of about 22%.

The coating composition is sprayed onto the sanded surface of a primedflexible bumper of a high density polyurethane which is reinforced witha steel bar. The composition is allowed to air dry for 16 hours andresults in a finish which is about 1 mil thick and that has excellentadhesion to the polyurethane substrate, excellent flexibility and formsa high gloss finish.

EXAMPLE 2 A white acrylic lacquer is prepared as follows:

Portion 1: Parts by weight Acetone 10.70 Ethylene glycol monoethyl etheracetate 24.70 Toluene 25.00 Alkyd resin plasticizer (35% coconut oil/61% ethylene glycol phthalate/4% ethylene glycol) 62.00

Portion 2:

30/70 acetone/toluene solvent) Portion 3:

1 White mill base (55% solids dispersion of titaniurn dioxide dispersedwith a resin blend of a methacrylate resin and cellulose acetatebutyrate in toluene and ethylene glycol monoethyl ether acetate) "187.60

Total 568.70

Parts by Volume Clear coating composition (prepared in Example 1) Whiteacrylic lacquer (prepared above) 100 Lacquer thinner (25.50%!- acetone/11.52% isopropanol/31.40% toluene/ 1 1.13 xylene/ 20.48 ethylene glycolmonoethylether acetate) Total 3 50 A primed flexible bumper of a highdensity polyurethane foam reinforced with a steel member (replacementpart) is sanded to provide a uniformly roughened surface. The clearcoating composition of Example 1 is then sprayed onto the bumper and airdried for 1 minute providing a finish of about 0.5 mil thick. Therefinish composition prepared above is then sprayed onto the bumper andair dried providing a finish about 2 /2 mils in thickness. The resultingfinish has excellent adhesion to the substrate, good flexibility and ahigh gloss and is considered an acceptable finish for automativebumpers.

High density polyurethane foam bumper which has previously been finishedby the original equipment manufacturer with an enamel is sanded and theclear coat of Example 1 and the above refinish composition are appliedas above and the resulting finish has good adhesion to the substrate, isflexible and glossy and forms an acceptable automotive refinish product.

Similar results are obtained with Nordel rubber coated bumpers andstyrene/butadiene rubber coated bumpers and parts molded from polyvinylchloride.

EXAMPLE 3 l- A blue acrylic lacquer is prepared as follows: Portion 1:Parts by Weight 9 Portion 1: Parts by Weight Indo blue pigmentdispersion (32.5% solids of -indanth'rone blue pigment dispersed withthe .above described resin in a solvent blend of toluene/methyl isobutylketone/ethylene glycol I monoethyl ether acetate having a pigment tobinder ratio of 44/ 100)- Portion 2:

Total 772.68

A refinish composition is then prepared by blending together thefollowing ingredients:

Parts by Volume Clear coating composition (prepared in Example 1) 100Bype acrylic lacquer (prepared above) 100 Lacquer thinner (described inExample 2) 150 Total 350 A primed flexible bumper of a high densitypolyurethane foam reinforced with a steel member (replacement part) issanded to provide a uniformly roughened surface. The clear coatingcomposition of Example 1 is then sprayed onto the bumper and air driedfor 1 minute providing a finish of about 0.5 mil in thickness. Therefinish composition prepared above is then sprayed onto the bumper andair dried providing a finish about 2 /2 mils in thickness. The resultingfinish has excellent adhesion to the substrate, good flexibility and ahigh gloss and is considered an acceptable finish for automotivebumpers.

High density polyurethane foam bumper which has previously been finishedby the original equipment manufacturer with an enamel is sanded and theclear coating of Example 1 and a coating of the above refinishcomposition are applied as above and the resulting finish had goodadhesion to the substrate, is flexible and glossy and for-ms anacceptable automotive bumper finish product.

Example 4 A white acrylic tinting lacquer is prepared as follows:

Parts by Weight White mill base (67.6% titanium dioxide pigment solidsdispersed with acrylic-oxazoline resin described hereinafter in asolvent mixture of methyl isobutyl ketone and toluene and having apigment/binder ratio of 636/100) Bentone mill base (25.7% benetonepigment solids dispersed with the above acrylic oxazoline polymerdescribed hereinafter in methyl isobutyl ketone/ ethyl glycol monoethylether acetate solvent blend and having a pigment to binder ratio of 45/100) Acrylic-oxazoline polymer solution (48% polymer solids of a polymerof methyl methacrylate/ethylacrylate/acrylonitrile/vinyl oxazoline talloil fatty acid ester in a weight ratio 55/ /5/25 in a mixture of estersand aromatic hydrocarbon solvents) Total 95.84

A pigmented polymer blend is then formed by mixing together thefollowing ingredients:

Parts by Weight White acrylic tinting lacquer (prepared above) 14.80CAB/plasticizer solution (27% solids of a solution of cellulose acetatebutyrate having a 38% butyryl content and a 2 second viscosity n-butylcyclohexyl phthalate (/10) in a solvent of 1:1:1 ofacetone/isopropanol/toluene) CAB /plasticizer/acrylic-oxazoline polymersolution (27% solids solution of cellulose acetate butyrate 2-secondviscosity, 38% butyryl content/butyl cyclohexylphthalate/acrylic-oxazoline polymer, described above in a weight ratio49.5/ 5.5/ 45 in a solvent of acetone/isopropanol/toluene in a ratio of3/1/1) Total 36.95

The refinish composition is prepared by blending together the followingingredients:

Parts by Volume Pigmented polymer blend (prepared above) Clear coatingcomposition (prepared in Example 1 100 Lacquer thinner (described inExample 2) Total 350 substrate, good flexibility and a high gloss and isconsidered an acceptable finish for automative bumpers.

High density polyurethane foam bumper which has previously been finishedby the original equipment manufacturer with a white enamel sander andthe clear coat of Example 1 is applied as above and the refinish coatare applied as above and air dried. The resulting finish has goodadhesion to the substrate, is flexible and glossy.

The invention claimed is:

1. A coating composition consisting essentially of 10- 50% by weight offilm forming binder and correspondingly 90-50% by weight of an organicsolvent for the binder wherein the binder consists essentially of (1)35-65% by weight, based on the weight of the binder, of a copolymerconsisting essentially of the reaciton product of 85-95% by weight ofmethyl methacrylate and correpondingly 10-20% by weight of an alkylacrylate or an alkyl methacrylate having 2-12 carbon atoms in the alkylgroups;

(2) 5-20% by weight, based on the weight of the binder, of a copolymerconsisting essentially of the reaction product of 85-95% by weight ofmethyl methacrylate and 5-15% by weight of polymerized adhesionpromoting monomer of the formula wherein n is 1-2, m is 2-3 and R and Rare selected from the group consisting of hydrogen, phenyl, benzyl, analkyl group having 1-12 carbon atoms, or 2,2- spirocyclohexyl; and

I)": (3 36-50% by weight, based gnthe weig ht jofx the 80-90% by weightof methyl ,methacrylate and 20- 10%.by weight of butyl .acrylate; v

(2) -.5-20,% by weight,-based on the weight of the binder, of acopolymer of the reaction product of 85-95% by weight of methylmethacrylate and 5- 15% by weight of3-(2-methacryloxyethyl)-2,2-.spirocyclohexyl oxazolidine,

(3) 30-50% by weight, based on the weight of the binder, of butyl benzylphthalate.

35The coating composition of claim 1 in which the binder consistsessentially of (1) 46-50% by weight, based on the weight of the,

binder, of a copolymer of the reaction product of 82% by weight ofmethyl methacrylate and 18% by weight of butyl acrylate,

ga -539a 10-14% by weight, basedon the Weight I v (3) 38-42% byweightfi-based on the-weightfof the 3,488,307 1/1970' Walys et a1. 2fiQ-23 AR MELVIN GOLDSTEIN, Primary Examiner W. c. DANISON, JR.', AssistantExaminer 117 132 B, 161 UZ, UN, UC;-26023-AR,31.'8 G,

32.8 N, 33.2 R,-33.4--R-, 33.6 'UA; 895, 901 r

